Restrict Anonymous settings

In reading this article http://support.microsoft.com/kb/890161, it suggests
changing restrict anymous setting to a 1 or 2. Am I correct in thinking that
if I change the setting to 2, the 1 NT pc we have will not be able to
authenticate to the domain? Also, I had a root forest domain and then a child
domain. Will this break any trust relationships bewteen the 2? All users
logon to the child domain for authentication. I read somewhere that I
shouldn't set the DCs to 2. Any insights?

Thanks
Deb H